A lot of people I think have a misguided mindset about aikido practice.

1. Because aikido is a "non-violent, non-confrontational" martial art, the dojo is a safe place to train. Wrong. Aikido is a martial art, period. The dojo IS a dangerous place. For me, I treat driving a car safer than training in aikido. The reason why I say driving is safer is because at least the road has rules, a lot of people don't know the rules while training in aikido (eg always throw outside, assess partner's ukemi, etc).

2. Never trust your partner just because aikido is based on "cooperation". We come across thousands of partners in our aikido careers and later you will gauge who is dangerous, who is prone to accidents, who doesn't care about uke. I've made a decision to avoid these kinds of people or minimize partnering with them. To me, it is not impolite or rude to do this. I always believe accidents are the fault of both parties: The one who caused the accident and the victim. You as a potential victim already have the ability to look for the signs to look for to avoid accidents and injury to yourself; use this ability to avoid accidents and injury.

3. You have a right to complain if you are being roughed up. Some nage's think that because uke's ability to take ukemi is advanced that they have a right to rough up uke. In you being uke, nage is just borrowing your body for him to learn so he needs to respect and appreciate this. Complaining is and setting expectations is a defense mechanism. Nobody's got any right to injure you. You also cannot bring back your body to it's original form with some injuries. A lot of people think that by complaining, you are being a wimp. This isn't the case. Better be a wimp who can train forever, than somebody tolerant who can't train at all.